Radial Polydactyly and the Incidence of Reoperation Using A New Classification System

Polydactyly is one of the more common congenital deformities with an incidence of 0.8 to 1.4 per 1000. Traditionally the Wassel Classification system has been used, which is based on the level of duplication seen on plain radiographs. Although it is helpful in describing the anatomic characteristics, it is somewhat limited with regards to surgical planning and postoperative outcomes. Chung and colleagues, recently proposed a new classification system that categorizes radial polydactyly based on morphologic features that provides helpful information to be used in surgical decision making. We reviewed all radial polydactyly cases that had undergone operative intervention at our center over a 10-year period to investigate if this new classification system correlates with the rate of reoperation.

A total of 60 thumbs in 54 patients that were treated surgically from 2000 to 2010 at our institution were included in this study. Only patients with a minimum follow-up of 2 years were included. The authors categorized all duplications based on the classification system proposed by Chung and colleagues: type I (Joint Type), type II (Single Epiphyseal Type), type III (Osteochondroma-like Type), and type IV (Hypoplastic Type). Statistical analysis was then used to look at this classification system as it relates to sex, family history, syndrome association, and the need for reoperation.

Of the 60 radial polydactyly cases, 37 (62%) were type I; 6 (10%) were type II; 6 (10%) were type III; and 11 (18%) were type IV. Six thumbs underwent reoperation for residual deformity-3 type I, 3 type II, and none of the types III or IV. No statistical significance was found when comparing classification group to sex, family history, syndrome association, laterality, or bilateral involvement. Statistical significance (P<0.05) was found between groups and the need for reoperation.

The new classification system proposed by Chung and colleagues is easy to use and can guide practitioners in their discussions with patients regarding surgical outcomes and possible need for revision surgery.